Current real-time rendering techniques of virtual representations of jewelry with gemstones do not address the shimmer and sparkle of real gemstones. Embodiments of the present invention use real-time rendering methods and systems that enable flash scintillation and fiery scintillation on the facets of virtual representations of gemstones as they are manipulated online by the customer. A 3D representation of a gemstone is displayed. In response to user input corresponding to the manipulation of the displayed 3D representation of the gemstone, scintillations at facets of the 3D representation of the gemstone are determined. The scintillations are determined by loading a scintillation factor from a look-up table corresponding to an angle of incidence of a light source to a facet of the gemstone. The determined scintillations at the facets of the gemstone are displayed for the user in real-time.